WO2017038086A1

WO2017038086A1 - Exhaust diffuser

Info

Publication number: WO2017038086A1
Application number: PCT/JP2016/003958
Authority: WO
Inventors: 拓也池口; 晃司寺内; 恵次追風; 直人阪井
Original assignee: 川崎重工業株式会社
Priority date: 2015-08-31
Filing date: 2016-08-30
Publication date: 2017-03-09
Also published as: GB2556798A8; GB201803441D0; CN107923261B; GB2556798A; GB2556798B; JP6546481B2; US20180328230A1; JP2017048683A; DE112016003468T5; US10851676B2; CN107923261A

Abstract

An exhaust diffuser is provided with an inner cylinder, an outer cylinder that together with the inner cylinder forms an exhaust passage widening rearward from the front, and at least one tubular strut linking the inner cylinder and the outer cylinder. The outer cylinder has a front conic section in front of the tubular strut, and an outer flare section that begins to widen in front of the tubular strut at a greater angle of inclination than the front conic section. The inner cylinder has a front strut section facing the front conic section and the outer flare section, and an inner flare section that begins to widen between the widest portion and the rear edge of the tubular strut.

Description

Exhaust diffuser

The present invention relates to an exhaust diffuser.

Conventionally, an exhaust diffuser that converts the dynamic pressure of the exhaust gas from the turbine into a static pressure is disposed downstream of the turbine. For example, Patent Document 1 discloses an exhaust diffuser incorporated in a gas turbine engine.

In the exhaust diffuser disclosed in Patent Document 1, the inner cylinder and the outer cylinder are connected by a plurality of struts. Between the inner cylinder and the outer cylinder, an exhaust passage that extends from the front toward the rear is formed. The struts have the same plate shape and are arranged on the same circumference at an equiangular pitch.

JP 2014-77441 A

By the way, some of the plurality of struts are formed into a tubular shape, and piping or the like is passed through the inside. However, when some of the struts are tubular and thickened in this way, the pressure loss increases in the region where the struts exist.

Therefore, an object of the present invention is to provide an exhaust diffuser that can reduce pressure loss caused by a tubular strut even when the tubular strut is included.

In order to solve the above-described problem, an exhaust diffuser according to one aspect of the present invention includes an outer cylinder that forms an exhaust passage that extends from the front toward the rear between the inner cylinder and the inner cylinder, At least one tubular strut connecting the inner cylinder and the outer cylinder, and the outer cylinder has a front cone portion in front of the tubular strut, and has a larger inclination angle than the front cone portion. It has an outer flare portion that starts to spread from the front side of the tubular strut, and the inner cylinder has a front straight portion that faces the front cone portion and the outer flare portion, and a maximum width portion and a rear portion of the tubular strut. It has an inside flare part which begins to spread from between the edges.

Here, “front” and “rear” refer to one side (upstream side of exhaust flow) and the other side (downstream side of exhaust flow) of the exhaust diffuser, respectively.

According to the above configuration, since the exhaust passage is enlarged by the outer flare portion in front of the tubular strut, the exhaust gas flowing through the exhaust passage is sufficiently decelerated and then flows between the tubular struts. Therefore, the pressure loss in the vicinity of the front edge of the tubular strut can be reduced. On the other hand, when there is no inner flare portion, the cross-sectional area of the exhaust passage increases rapidly due to the decrease in the area occupied by the tubular struts behind the maximum width portion of the tubular struts. On the other hand, if there is an inner flare part, such a rapid increase in the cross-sectional area of the exhaust passage can be mitigated by the inner flare part. Thereby, pressure loss can be reduced even in the vicinity of the rear edge of the tubular strut.

A part of the outer cylinder and a part of the inner cylinder may be integrally formed with the tubular strut by casting. According to this configuration, an exhaust diffuser suitable for medium-sized and small-sized gas turbine engines can be realized.

The outer cylinder has an outer straight portion extending rearward from the rear end of the outer flare portion beyond the maximum width portion of the tubular strut, and a rear conical portion expanding in diameter from the rear end of the outer straight portion, The inner cylinder may have a rear straight portion extending rearward from a rear end of the inner flare portion. According to this configuration, the outer cylinder is not formed with a recess that is recessed radially outward from the exhaust channel, and the inner cylinder is not formed with a recess that is recessed radially inward from the exhaust channel. When a part of the inner cylinder and a part of the inner cylinder are manufactured together with the tubular strut by casting, the number of mold divisions can be reduced.

The exhaust diffuser may further include at least one flat strut that connects the inner cylinder and the outer cylinder and overlaps the tubular strut in the axial direction of the exhaust diffuser. According to this configuration, a thin strut can be employed at a place where there is no piping or the like, and a large cross-sectional area of the exhaust passage can be ensured. Thereby, pressure loss can be made smaller than when all the struts are tubular struts.

The front edge of the flat strut may be located in front of the front edge of the tubular strut, and the rear edge of the flat strut may be located behind the maximum width portion of the tubular strut. According to this configuration, since the cross-sectional area of the exhaust passage is reduced by the flat strut and then greatly reduced by the tubular strut, the cross-sectional area of the exhaust passage can be changed gently. Thereby, compared with the case where the front edge of a tubular strut and the front edge of a flat strut correspond, pressure loss can be made small.

The trailing edge of the flat strut may be positioned in front of the trailing edge of the tubular strut. According to this configuration, the exhaust gas flowing through the exhaust flow passage merges in the vicinity of the trailing edge of the flat strut and then merges in the vicinity of the trailing edge of the tubular strut. Thereby, a flow can be stabilized.

An exhaust diffuser according to another aspect of the present invention includes an inner cylinder, an outer cylinder that forms an exhaust passage that extends from the front toward the rear, and the inner cylinder and the outer cylinder. At least one tubular strut that connects the inner cylinder and the outer cylinder, and at least one flat strut that overlaps the tubular strut in the axial direction of the exhaust diffuser, and the front of the flat strut The edge is located forward of the front edge of the tubular strut, and the rear edge of the flat strut is located behind the maximum width portion of the tubular strut.

According to the above configuration, since the cross-sectional area of the exhaust passage is reduced by the flat strut and then greatly reduced by the tubular strut, the cross-sectional area of the exhaust passage can be changed gently. Thereby, compared with the case where the front edge of a tubular strut and the front edge of a flat strut correspond, pressure loss can be made small.

In the exhaust diffuser from the other side surface, the trailing edge of the flat strut may be positioned forward of the trailing edge of the tubular strut. According to this configuration, the exhaust gas flowing through the exhaust flow passage merges in the vicinity of the trailing edge of the flat strut and then merges in the vicinity of the trailing edge of the tubular strut. Thereby, a flow can be stabilized.

In the exhaust diffuser from the other side surface, a part of the outer cylinder and a part of the inner cylinder may be integrally formed with the tubular strut by casting. According to this configuration, an exhaust diffuser suitable for medium-sized and small-sized gas turbine engines can be realized.

According to the present invention, even if a tubular strut is included, the pressure loss due to the tubular strut can be reduced.

1 is a schematic configuration diagram of a gas turbine engine in which an exhaust diffuser according to an embodiment of the present invention is incorporated. It is sectional drawing of an exhaust diffuser. FIG. 3 is a sectional view taken along line III-III in FIG. 2. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3.

FIG. 1 shows a gas turbine engine 1 in which an exhaust diffuser 2 according to an embodiment of the present invention is incorporated. Hereinafter, one (the upstream side of the exhaust flow) in the axial direction (horizontal direction in the present embodiment) of the exhaust diffuser 2 is referred to as the front, and the other (the downstream side of the exhaust flow) is referred to as the rear.

The gas turbine engine 1 includes a compressor 11, a combustion chamber 12 and a turbine 13. The exhaust diffuser 2 is disposed downstream of the turbine 13. The gas turbine engine 1 also includes a rotor 14 that penetrates the compressor 11 and the turbine 13. A generator 15 is connected to the front end of the rotor 14.

2 and 3, the exhaust diffuser 2 includes an inner cylinder 3 and an outer cylinder 4. An exhaust passage 21 is formed between the inner cylinder 3 and the outer cylinder 4 so as to expand from the front toward the rear. In this embodiment, the inner cylinder 3 and the outer cylinder 4 are mutually connected by a plurality of (two in the illustrated example) tubular struts 5 and a plurality of (four in the illustrated example) flat struts 6 extending in the radial direction of the exhaust diffuser 2. It is connected. However, each of the tubular struts 5 and the flat struts 6 may be at least one, and the number of the tubular struts 5 and the number of the flat struts 6 can be appropriately determined.

The tubular strut 5 and the flat strut 6 are arranged in the circumferential direction of the exhaust diffuser 2. Each flat strut 6 is parallel to the radial direction of the exhaust diffuser 2. However, each flat strut 6 may be inclined with respect to the radial direction of the exhaust diffuser 2. In the present embodiment, two tubular struts 5 are arranged above and below the inner cylinder 3, and two flat struts 6 are arranged on the right and left sides of the inner cylinder 3, respectively.

The exhaust diffuser 2 of this embodiment is suitable for medium and small gas turbine engines. For this reason, a part of the outer cylinder 4 and a part of the inner cylinder 3 are integrally formed with the tubular strut 5 and the flat strut 6 by casting.

More specifically, the outer cylinder 4 is divided into a front piece 4A and a rear piece 4B, and the inner cylinder 3 is divided into a front piece 3A and a rear piece 3B. And the front piece 4A of the outer cylinder 4 and the front piece 3A of the inner cylinder 3 are integrally formed with the tubular strut 5 and the flat strut 6 by casting. Each of the rear piece 4B of the outer cylinder 4 and the rear piece 3B of the inner cylinder 3 is manufactured by sheet metal processing, for example.

Further, in this embodiment, the flat strut 6 protrudes forward from the tubular strut 5. In other words, the flat strut 6 partially overlaps the tubular strut 5 in the axial direction of the exhaust diffuser 2.

More specifically, as shown in FIG. 4, the cross-sectional shape of each tubular strut 5 is a waterdrop shape that sharpens toward the rear, and the front from the maximum width portion 55 is semicircular, and the rear from the maximum width portion 55 is substantially V-shaped. Is. Here, “width” refers to the thickness of the tubular strut 5 in the circumferential direction of the exhaust diffuser 2. The front piece 4A of the outer cylinder 4 and the front piece 3A of the inner cylinder 3 are respectively provided with openings 45 and 35 (see FIGS. 2 and 3) having the same shape as the internal space of the tubular strut 5.

The front edge 61 of the flat strut 6 is located in front of the front edge 51 of the tubular strut 5 by a distance A. Further, the rear edge 62 of the flat strut 6 is positioned forward by a distance B from the rear edge 52 of the tubular strut 5. However, the rear edge 62 of the flat strut 6 is located behind the maximum width portion 55 of the tubular strut 5. Here, the “front edge” and the “rear edge” refer to straight edges of portions having a constant cross-sectional shape in each of the tubular strut 5 and the flat strut 6.

2, the outer cylinder 4 has a front conical portion 41, an outer flare portion 42, an outer straight portion 43, and a rear conical portion 44 in order from the front. These portions 41 to 44 constitute a continuous inward wall surface. That is, the front end of the front cone portion 41 is the front end of the outer cylinder 4, the rear end of the rear cone portion 44 is the rear end of the outer cylinder 4, and the rear end and the front end of adjacent portions are connected to each other. Yes. The front cone part 41, the outer flare part 42, and the outer straight part 43 are components of the front piece 4A, and the rear cone part 44 is a component of the rear piece 4B.

The front cone part 41 is located in front of the tubular strut 5 and the flat strut 6. The front cone portion 41 has a diameter that increases toward the rear at a relatively gentle inclination angle.

The outer flare portion 42 starts to spread from the front side with respect to the tubular strut 5 and the flat strut 6 at a larger inclination angle than the front cone portion 41. In the present embodiment, the rear end of the outer flare portion 42 is located behind the front edge 51 of the tubular strut 5. However, the rear end of the outer flare portion 42 may be located at the same position as the front edge 51 of the tubular strut 5, or may be located forward of the front edge 51 of the tubular strut 5.

For example, the outer flare portion 42 is formed by reducing the cross-sectional area of the exhaust passage 21 due to the tubular strut 5 in the vicinity of the front edge 51 of the tubular strut 5 (in some cases, in the vicinity of the front edge 61 of the flat strut 6. The diameter of the outer cylinder 4 is increased so as to cancel (and not necessarily to zero) the reduction in the cross-sectional area of the exhaust passage 21 caused by the flat strut 6.

The outer straight portion 43 extends rearward from the rear end of the outer flare portion 42 beyond the maximum width portion 55 of the tubular strut 5. In the present embodiment, the rear end of the outer straight portion 43 is located behind the rear edge 52 of the tubular strut 5. However, the rear end of the outer straight portion 43 may be located at the same position as the rear edge 52 of the tubular strut 5 or may be located forward of the rear edge 52 of the tubular strut 5.

The rear conical part 44 is enlarged in diameter from the rear end of the outer straight part 43 toward the rear. The inclination angle of the rear cone portion 44 may be the same as or different from the inclination angle of the front cone portion 41.

On the other hand, the inner cylinder 3 has a front straight part 31, an inner flare part 32, and a rear straight part 33 in order from the front. These portions 31 to 33 constitute a continuous outward wall surface. That is, the front end of the front straight portion 31 is the front end of the inner cylinder 3, the rear end of the rear straight portion 33 is the rear end of the inner cylinder 3, and the rear end and the front end of adjacent portions are connected to each other. Yes. The front straight portion 31 and the inner flare portion 32 are components of the front piece 3A, and the rear straight portion 33 is a component of the rear piece 3B.

The front straight portion 31 extends rearward from the front end of the inner cylinder 3 beyond the maximum width portion 55 of the tubular strut 5. For this reason, the front straight portion 31 faces the entire front conical portion 41 and the outer flare portion 42 of the outer cylinder 4 and also faces a part of the outer straight portion 43.

The inner flare portion 32 starts to spread between the maximum width portion 55 and the rear edge 52 of the tubular strut 5. The rear end of the inner flare portion 32 is located behind the rear edge 52 of the tubular strut 5.

For example, the inner flare portion 32 increases the cross-sectional area of the exhaust passage 21 due to the tubular strut 5 in the vicinity of the rear edge 52 of the tubular strut 5 (in some cases, in the vicinity of the rear edge 62 of the flat strut 6. The diameter of the inner cylinder 3 is increased so as to cancel out (and increase in the cross-sectional area of the exhaust passage 21 caused by the flat strut 6) (not necessarily zero).

The rear straight portion 33 extends rearward from the rear end of the inner flare portion 32 and faces the rear conical portion 44 of the outer cylinder 4.

As described above, in the exhaust diffuser 2 of the present embodiment, the exhaust passage 21 is enlarged by the outer flare portion 42 in front of the tubular strut 5, so that the exhaust flowing through the exhaust passage 21 is sufficiently decelerated. It flows between the tubular struts 5. Therefore, the pressure loss in the vicinity of the front edge 51 of the tubular strut 5 can be reduced. On the other hand, in the absence of the inner flare portion 32, the cross-sectional area of the exhaust passage 21 increases rapidly due to the decrease in the area occupied by the tubular strut 5 behind the maximum width portion 55 of the tubular strut 5. On the other hand, if there is the inner flare part 32, the rapid increase in the cross-sectional area of the exhaust passage 21 can be mitigated by the inner flare part 32. Thereby, the pressure loss can be reduced even in the vicinity of the rear edge 52 of the tubular strut 5.

Furthermore, in the present embodiment, since the front edge 61 of the flat strut 6 is positioned in front of the front edge 51 of the tubular strut 5, the cross-sectional area of the exhaust passage 21 is reduced slightly by the flat strut 6. It is greatly reduced by the tubular strut 5. For this reason, the cross-sectional area of the exhaust passage 21 can be changed gently. Thereby, compared with the case where the front edge 51 of the tubular strut 5 and the front edge 61 of the flat strut 6 correspond, pressure loss can be made small.

Further, since the trailing edge 62 of the flat strut 6 is located in front of the trailing edge 52 of the tubular strut 5, the tubular strut 5 is connected after the exhaust gas flowing through the exhaust passage 21 merges in the vicinity of the trailing edge 62 of the flat strut 6. Merges in the vicinity of the trailing edge 52. Thereby, a flow can be stabilized.

Further, in the present embodiment, the outer cylinder 4 is not formed with a recess that is recessed radially outward from the exhaust flow path 21, and the inner cylinder 3 is not formed with a recess that is recessed radially inward from the exhaust flow path. . For this reason, when manufacturing the front piece 4A of the outer cylinder 4 and the front piece 3A of the inner cylinder 3 together with the tubular strut 5 and the flat strut 6 by casting, the number of divisions of the mold (for example, a wooden mold) can be reduced. .

(Modification)
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

For example, the exhaust diffuser 2 is not necessarily incorporated into the gas turbine engine 1, and may be disposed downstream of the steam turbine, for example.

In the axial direction of the exhaust diffuser 2, the flat strut 6 does not necessarily overlap with the tubular strut 5, and the flat strut 6 may overlap with the tubular strut 5 as a whole.

Furthermore, the flat strut 6 is not necessarily required, and only a plurality of tubular struts 5 may be provided. However, if at least one tubular strut 5 and at least one flat strut 6 are provided as in the above-described embodiment, a thin strut can be adopted in a place where there is no piping or the like, and the exhaust passage 21 is disconnected. A large area can be secured. Thereby, compared with the case where all the struts are made into the tubular strut 5, pressure loss can be made small.

Further, the front end of the outer flare portion 42 may be located behind the front edge 61 of the flat strut 6. However, if the front end of the outer flare part 42 is located in front of the front edge 61 of the flat strut 6 as in the above embodiment, the speed of the exhaust gas flowing between the flat struts 6 can be reduced.

Further, the rear edge 62 of the flat strut 6 does not necessarily have to be positioned forward of the rear edge 52 of the tubular strut 5, and is the same position as the rear edge 52 of the tubular strut 5 or the rear edge 52 of the tubular strut 5. May be located rearward.

Although not shown, an intermediate cone portion having the same inclination angle as that of the rear cone portion 44 may be provided instead of the outer straight portion 43 of the outer cylinder 4. Furthermore, instead of the rear straight portion 33 of the inner cylinder 3, a conical portion whose diameter is reduced from the rear end of the inner flare portion 32 is adopted, and instead of the rear conical portion 44 of the outer cylinder 4, the straight portion is It may be adopted.

Further, each of the front piece 4A of the outer cylinder 4 and the front piece 3A of the inner cylinder 3 may be manufactured by sheet metal processing. Furthermore, each of the outer cylinder 4 and the inner cylinder 3 may be a single member.

By the way, paying attention to the positional relationship between the tubular strut 5 and the flat strut 6 of the above embodiment, the outer cylinder 4 does not have the outer flare part 42 and the inner cylinder 3 does not have the inner flare part 32. Also good. That is, in the above-described embodiment, since the front edge 61 of the flat strut 6 is positioned in front of the front edge 51 of the tubular strut 5, the cross-sectional area of the exhaust passage 21 is reduced by the flat strut 6 to a small extent. It is greatly reduced by the tubular strut 5. For this reason, the cross-sectional area of the exhaust passage 21 can be changed gently. Thereby, compared with the case where the front edge 51 of the tubular strut 5 and the front edge 61 of the flat strut 6 correspond, pressure loss can be made small. Thus, when paying attention to the positional relationship between the tubular strut 5 and the flat strut 6 of the embodiment, the inner cylinder 3 and the outer cylinder 4 have the exhaust passage 21 formed between them from the front to the rear. Any shape may be used as long as it spreads out.

Even when attention is paid to the positional relationship between the tubular strut 5 and the flat strut 6 in the embodiment, the rear edge 62 of the flat strut 6 does not necessarily have to be located in front of the rear edge 52 of the tubular strut 5. Instead, it may be located at the same position as the rear edge 52 of the tubular strut 5 or behind the rear edge 52 of the tubular strut 5. Further, each of the outer cylinder 4 and the inner cylinder 3 may be manufactured by sheet metal processing as a whole or may be a single member.

2 Exhaust diffuser 21 Exhaust flow path 3 Inner cylinder 31 Front straight part 32 Inner flare part 33 Rear straight part 4 Outer cylinder 41 Front conical part 42 Outer flare part 43 Outer straight part 44 Rear conical part 5 Tubular strut 51 Front edge 52 Trailing edge 55 Maximum width 6 Flat strut 61 Leading edge 62 Trailing edge

Claims

An inner cylinder,
An outer cylinder that forms an exhaust passage extending from the front to the rear between the inner cylinder and the inner cylinder;
And at least one tubular strut connecting the inner cylinder and the outer cylinder,
The outer cylinder has a front conical portion in front of the tubular strut, and an outer flare portion that starts to spread from the front with respect to the tubular strut at a larger inclination angle than the front conical portion,
The inner cylinder has a front straight portion facing the front conical portion and the outer flare portion, and has an inner flare portion that starts to spread from between the maximum width portion and the rear edge of the tubular strut. .
The exhaust diffuser according to claim 1, wherein a part of the outer cylinder and a part of the inner cylinder are integrally formed with the tubular strut by casting.
The outer cylinder has an outer straight portion extending rearward from the rear end of the outer flare portion beyond the maximum width portion of the tubular strut, and a rear conical portion expanding in diameter from the rear end of the outer straight portion,
The exhaust diffuser according to claim 1 or 2, wherein the inner cylinder has a rear straight portion extending rearward from a rear end of the inner flare portion.
The exhaust diffuser according to any one of claims 1 to 3, further comprising at least one flat strut that connects the inner cylinder and the outer cylinder and overlaps the tubular strut in the axial direction of the exhaust diffuser.
The front edge of the flat strut is located in front of the front edge of the tubular strut;
The exhaust diffuser according to claim 4, wherein a rear edge of the flat strut is located behind a maximum width portion of the tubular strut.
The exhaust diffuser according to claim 5, wherein a rear edge of the flat strut is located in front of a rear edge of the tubular strut.
An inner cylinder,
An outer cylinder that forms an exhaust passage extending from the front to the rear between the inner cylinder and the inner cylinder;
At least one tubular strut connecting the inner cylinder and the outer cylinder;
Connecting the inner cylinder and the outer cylinder, and including at least one flat strut overlapping the tubular strut in the axial direction of the exhaust diffuser,
The front edge of the flat strut is located in front of the front edge of the tubular strut;
The exhaust diffuser, wherein a rear edge of the flat strut is located behind a maximum width portion of the tubular strut.
The exhaust diffuser according to claim 7, wherein a rear edge of the flat strut is located in front of a rear edge of the tubular strut.
The exhaust diffuser according to claim 7 or 8, wherein a part of the outer cylinder and a part of the inner cylinder are integrally formed with the tubular strut by casting.